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Wildfires Belched Carbon Monoxide

Posted on: Thursday, 30 June 2005, 09:00 CDT

Wildfires that burned about 13 million acres in Alaska and Canada last summer pumped more carbon monoxide into the air than tailpipes and smokestacks in the U.S. did during the same period, Boulder researchers said.

Winds blew some of the wildfire-produced carbon monoxide thousands of miles to the east, briefly elevating levels of the gas in New England and as far away as Europe, according to a research team headed by Gabriele Pfister, of the National Center for Atmospheric Research in Boulder.

Pollutants from Alaskan and Canadian wildfires also caused temporary increases in ground-level ozone, a major ingredient in smog. Carbon monoxide and other pollutants released by wildfires react in the presence of sunlight to form ozone.

Ozone levels briefly surged 25 percent in parts of New England, and 10 percent in Europe, because of the Canadian and Alaskan wildfires of 2004, the researchers said.

"What the fires really showed us is how everything is linked together," Pfister said. "There is really a strong impact that the fires have on ozone levels all the way to Europe.

"So if you are in a region where you already have high ozone background concentrations due to local sources, this contribution from the fires can have significant effects on human health and the environment," she said.

The NCAR study was published this month in the journal Geophysical Research Letters.

The researchers used satellites, airborne instruments and computer models to measure the pollutants and track their movement.

Satellites were used to estimate the amount of carbon monoxide released by the wildfires. From June through August 2004, the Alaskan and Canadian wildfires released about 33 million tons, Pfister said.

During the same period, human activities in the continental U.S. emitted 27.5 million tons.

Carbon monoxide is a poisonous gas produced by the incomplete combustion of carbon-containing fuels such as gasoline, coal and wood.

Computer models simulated the eastward movement of airborne pollutants from the fires. Airborne instruments sampled carbon monoxide and ozone levels at various locations in North America and Europe.

Then computer projections and on-site measurements were compared to determine the fires' contribution to pollution levels at a given site.

Exposure to carbon monoxide reduces the blood's ability to carry oxygen. At low levels, the health threat is most serious for those who suffer from cardiovascular disease.

Ground-level ozone is a powerful respiratory irritant that can cause shortness of breath, chest pain, wheezing and coughing.

Long-term, repeated exposure to high levels of ozone may lead to large reductions in lung function, inflammation of the lung lining and increased respiratory discomfort, according to the American Lung Association.

Wildfires burned about 5 million acres in Alaska last year, according to the National Interagency Fire Center.

Canadian wildfires burned 8.1 million acres in 2004, according to the Canadian Interagency Forest Fire Centre.

Source: Rocky Mountain News

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